1. Technical Field
The invention relates to a flow path unit which forms a liquid flow path through which liquid flows, a liquid ejecting head, and a liquid ejecting apparatus.
2. Related Art
In the related art, apparatuses are known which have a flow path through which liquid flows. In addition, a flow path unit is also known which configures a part of this flow path. The flow path unit has a pressure chamber, where the pressure is changed, in a part and connects a flow path where liquid is supplied and a flow path on the side where liquid is discharged.
In addition, a configuration where the flow path is covered with a coating film in order to protect wall surfaces of the flow path from the liquid is disclosed (for example, refer to JP-A-2009-202401, JP-UM-A-5-60844, and JP-A-10-250078. The coating film is used in order to protect the flow path from corrosion due to the characteristics of the liquids which are used or deterioration thereof over time.
In a case where a flow path is configured by laminating a plurality of substrates, when the positional alignment precision of the surfaces where the substrates are bonded with each other (also described below as the bonding surfaces) is low, there are cases where the flow path is not properly formed. For example, when the substrates are not correctly bonded with each other via the bonding surface, there are cases where differences in level occur in the joints of the flow path or where the flow path is not properly sealed at the joints. In a case where differences in level occur in the joints, air bubbles are trapped in the difference in level, which is not preferable.